Thin film transistor array substrate

ABSTRACT

An organic light emitting diode (OLED) display device, and a method for manufacturing the OLED display device are discussed. The OLED display device according to one embodiment includes a substrate; a first bank pattern formed on the substrate and in an emission region and a non-emission region; a second bank pattern formed on the first bank pattern; an organic emission layer formed on the substrate in the emission region; and a planarization film formed on the substrate to include an opening under the first and second bank patterns in the non-emission region. The second bank pattern is on the first bank pattern in the non-emission region, and the first bank pattern is in the opening of the planarization film in the non-emission region.

The present application claims priority under 35 U.S.C. §119(a) ofKorean Patent Application No. 10-2014-0169057 filed on Nov. 28, 2014which is hereby incorporated by reference in its entirety.

BACKGROUND

1. Field of the Invention

The present application relates to a thin film transistor arraysubstrate, and more particularly to a thin film transistor arraysubstrate adapted to prevent the generation of thickness deviations inan organic emission layer which is included in an organic light emittingdiode (OLED) display device with the thin film transistor arraysubstrate.

2. Description of the Related Art

Display devices include display devices with backlight units and OLEDdisplay devices using self-luminous elements that do not require aseparated backlight unit. In accordance therewith, an OLED displaydevice using a self-luminous element can be thin and have low powerconsumption.

The OLED display device can include an organic light emitting elementincluding an anode electrode, a cathode electrode and an organicemission layer interposed between the two electrodes. An organic lightemitting element enables generation of excitons by recombining holes andelectrons from the anode and cathode electrodes into the organicemission layer. Also, the organic light emitting element emits light bythe excitons transitioning from an excited state to a stable state.

The organic emission layer can be formed using a vapor depositionmethod. An ink-jet printing process can be used to form the organicemission layer on a large-sized substrate by dropping a liquefiedorganic emission material.

Such an organic emission layer has thicker edge areas adjacent to a bankpattern compared to a central area surrounded by the bank pattern. Thisresults from the fact that the edge portion of the organic emissionlayer is hardened at a slower speed than a hardening speed of thecentral portion of the organic emission layer; and an organic emissionmaterial is internally removed from the central area of the organicemission layer to the edge area of the organic emission layer due to ahardening phenomenon of the organic emission material progresses fromthe central area to the edge area of the organic emission layer.

BRIEF SUMMARY

Embodiments of the present application are directed to a thin filmtransistor array substrate that substantially obviates one or more ofproblems due to the limitations and disadvantages of the related art. Athin film transistor array substrate according to one embodiment isadapted to reduce the thickness of an organic emission layer and preventthe non-uniform formation of the organic emission layer to externallyexpose a color filter layer. The exposed color filter layer is disposedunder a planarization film, through the planarization film within anon-emission region.

Additional features and advantages of the embodiments will be set forthin the description which follows, and in part will be apparent from thedescription, or can be learned by practice of the embodiments. Theadvantages of the embodiments will be realized and attained by thestructure particularly pointed out in the written description and claimshereof as well as the appended drawings.

To solve the above-mentioned problems, a thin film transistor arraysubstrate according to a general aspect of the present embodimentincludes a substrate including an emission region and a non-emissionregion, a color filter layer disposed on the substrate, a planarizationlayer disposed on the color filter layer and configured to remove atleast a part of the non-emission region corresponding to theplanarization layer. The thin film transistor array substrate alsoincludes a first electrode disposed on a part of the planarization film,a first bank pattern configured to expose a part of an upper surface ofthe first electrode and expand up to the non-emission region. The thinfilm transistor array substrate also includes a second bank patterndisposed on the first bank pattern within the non-emission region. As aresult, the thin film transistor array substrate reduces the thicknessof the second bank pattern to uniformly form an organic emission layer.

Other systems, methods, features and advantages will become, apparent toone with skill in the art upon examination of the following figures anddetailed description. The systems, methods, features and advantagesincluded within this description are within the scope of the presentinvention, and are protected by the following claims. Nothing in thissection should be taken as a limitation on those claims. Further aspectsand advantages are discussed below in conjunction with the embodiments.It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the embodiments and are incorporated herein andconstitute a part of this application, illustrate embodiments of thepresent invention and together with the description serve to explain theinvention. In the drawings:

FIG. 1 is a cross-sectional view showing a thin film transistor arraysubstrate of an OLED device according to a first embodiment of thepresent invention;

FIG. 2 is a cross-sectional view showing a non-emission region of thethin film transistor array substrate according to the first embodiment;

FIGS. 3A through 3C are cross-sectional views illustrating a method offabricating a thin film transistor array substrate of an OLED displaydevice according to the first embodiment;

FIG. 4 is a cross-sectional view showing a thin film transistor arraysubstrate of an OLED display device according to a second embodiment ofthe present invention;

FIG. 5 is a cross-sectional view largely showing a non-emission regionof the thin film transistor array substrate according to the secondembodiment;

FIGS. 6A through 6C are cross-sectional views illustrating a method offabricating a thin film transistor array substrate of an OLED displaydevice according to the second embodiment of the present invention;

FIG. 7 is a cross-sectional view showing a thin film transistor arraysubstrate of an OLED display device according to a third embodiment ofthe present invention;

FIG. 8 is a cross-sectional view showing a thin film transistor arraysubstrate of an OLED display device according to a fourth embodiment ofthe present invention; and

FIG. 9 is a photograph showing a non-emission region of a thin filmtransistor array substrate of an OLED display device according to afifth embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings. These embodiments introduced hereinafter are provided asexamples to convey the spirit of the invention to the ordinary skilledperson in the art. The invention is not limited to the embodimentsdescribed here. The size, thickness and so on of a device as shown inthe embodiments are provided for convenience of explanation. Whereverpossible, the same reference numbers are used throughout this disclosureincluding the drawings to refer to the same or like parts.

FIGS. 1 and 2 illustrate a thin film transistor array substrate of anOLED display device according to a first embodiment of the presentinvention. In further detail, FIG. 1 is a cross-sectional view showing athin film transistor array substrate of an OLED display device accordingto the first embodiment of the present invention; and FIG. 2 is across-sectional view largely showing a non-emission region of a thinfilm transistor array substrate according to the first embodiment. Thethin film transistor array substrate of an OLED display device accordingto the first embodiment of the present invention can include, forexample, a thin film transistor, a color filter layer 101 and an organiclight emitting element.

The thin film transistor includes a semiconductor layer 201, a gateinsulation film 202, a gate electrode 203, an inter-layer insulationfilm 204, a source electrode 205, a drain electrode 206, and a bufferlayer 207. The color filter layer 101 includes a red color filterpattern 101 a, a green color filter pattern 101 b and a blue colorfilter pattern. The organic light emitting element includes a firstelectrode 103, an organic emission layer 106 and a second electrode 107.The organic emission layer 106 can be formed by jetting or dropping aliquefied organic emission material into a region surrounded with asecond bank pattern 105 using one of a spin coating method, an ink-jetmethod and a slot die method and then hardening the jetted or droppedorganic emission material.

Because, in the related art, an organic emission layer must be formed tohave a thicker edge portion adjacent to the bank pattern compared to thecentral portion within the region surrounded by the bank pattern, anaperture ratio of the OLED display device must become lower. To improvethe aperture ratio of the OLED display device, the upper surface of anorganic emission layer can be flattened throughout an entire regionincluding an edge region adjacent to a bank pattern. The flattening ofthe upper surface of an organic emission layer can form a first bankpattern and a second bank pattern disposed on the first bank pattern. Inthis case, the second bank pattern disposed on the first bank patternmust be thickened. As a result, the thickened second bank pattern cancause an etchant to intrude between the first and the second bankpatterns during a photolithography process. In particular, in relatedart, the photolithography process which is used for patterning thesecond bank pattern can cause generation of a curling phenomenon of thesecond bank pattern and deterioration of the flatness of the organicemission layer. The curling phenomenon of the second bank pattern can begenerated due to the second bank pattern having a very large thicknessin a contact hole which is formed in a planarization film and used toconnect a first electrode of the organic light emitting element and thedrain electrode of the thin film transistor.

To address this matter, the OLED display device according to the firstembodiment of the present disclosure disposes a planarization film 102on regions of the color filter layer 101 not including a boundary regionbetween color filter patterns different from each other within a secondnon-emission region NA2. Also, a second bank pattern 105 is disposed inthe boundary region between the color filter patterns different fromeach other. As such, the thickness of the second bank pattern 105 candecrease.

In further detail, the thin film transistor array substrate of the OLEDdisplay device according to the first embodiment of the presentinvention includes the color filter layer 101 disposed on a substrate100 which is defined into an emission region AA and first and secondnon-emission regions NA1 and NA2. As such, a thin film transistor arraysubstrate of the OLED display device according to the first embodimentof the present invention is defined into the emission region AA and thefirst and second non-emission regions NA1 and NA2. The firstnon-emission region NA1 is used as a driver region in which the thinfilm transistor is disposed. The second non-emission region NA2 is apixel region that does not emit light and does not include the thin filmtransistor.

The planarization film 102 is disposed on the substrate 100 providedwith the color filter layer 101 (refer to FIG. 3C), but theplanarization film 102 cannot be disposed in the boundary region betweenthe color filter patterns different from each other. For example, theplanarization film 102 cannot be disposed in a boundary region between ared color filter pattern 101 a and a green color filter pattern 101 b.Also, the planarization film 102 cannot be disposed in a boundary regionbetween the green color filter pattern 101 b and a blue color filterpattern. Also, the planarization film 102 cannot be disposed in aboundary region between the blue color filter pattern and the red colorfilter pattern 101 a.

In other words, an opening can be formed in the planarization film 102within the second non-emission region NA2 to separate the planarizationfilm in two portions. The opening can be formed by removing a part ofthe planarization film 102 from one boundary between the different colorfilter patterns. For example, the opening formed in the planarizationfilm 102 can expose the boundary between the red color filter pattern101 a and the green color filter pattern 101 b. Or, the opening can beformed in a boundary between the green color filter pattern 101 b andthe blue color filter pattern. Also, the opening can be formed in aboundary between the blue color filter pattern and the red color filterpattern 101 a.

The first electrode 103 of the organic light emitting element can bedisposed on the planarization film 102 within the emission region AA.Such a first electrode 103 can be used as an anode electrode.Alternatively, the first electrode 103 can be used as a cathodeelectrode. Hereinafter, the first electrode 103 used as the anodeelectrode will be described in the first embodiment.

Also, the first electrode 103 can be formed in a single layer using arelatively high transparent conductive material. As such, a bottomemission type OLED display device emitting light from the secondelectrode of the organic light emitting element toward the firstelectrode 103 of the organic light emitting element can be implemented.Alternatively, a reflection layer disposed under the first electrode 103can further be included in the OLED display device. In accordancetherewith, a top emission type OLED display device reflects light, whichis emitted from the second electrode toward the first electrode 103, andoutputs light in an upward direction. Alternatively, the first electrode103 can be formed in a multi-layered structure.

For example, the first electrode 103 can be formed in a triple-layeredstructure including a first layer, a second layer disposed on the firstlayer and a third layer disposed on the second layer. In this case, thefirst layer and the third layer can be each formed from a transparentconductive material. The transparent conductive material can be one ofindium-tin-oxide (ITO) and indium-zinc-oxide (IZO). The second layer canbe a reflection layer, and one of a metal layer and a metal-alloy layer.For example, the second layer can be one of a silver layer and ametal-alloy layer including silver Ag. Therefore, the top emission typeOLED display device reflecting light, which is emitted from the secondelectrode toward the first electrode 103, in an upward direction can beimplemented.

A first bank pattern 104 is disposed on the first and secondnon-emission regions NA1 and NA2 of the substrate 100 provided with thefirst electrode 103 of the organic light emitting element. The firstbank pattern 104 can be formed in such a manner as to cover edges of thefirst electrode 103. In other words, the first bank pattern 104 can bedisposed to expose a part of the upper surface of the first electrode103 corresponding to the emission region AA. As such, a currentconcentration in the edge portion of the first electrode 103 can beprevented.

Such a first bank pattern 104 is disposed on the edges of the firstelectrode 103. Also the first bank pattern 104 can be disposed in theopening exposing a boundary between the color filter patterns differentfrom each other within the second non-emission region NA2 by expendingfrom one edge of the first electrode 103 of an organic light emittingelement up to the second non-emission region NA2. A second bank pattern105 can be disposed in such a manner as to overlap with the first bankpattern 104 disposed in the opening. In other words, the first bankpattern 104 can be disposed in the opening and the second bank pattern105 can be disposed on the first bank pattern 104 opposite to theopening.

In this manner, not only the opening is formed by two portions of theplanarization film 102 being separated from and disposed adjacently toeach other. The first bank pattern 104 and also the second bank pattern105 are disposed in the opening. As such, the second bank pattern 105disposed above the planarization film 102 can be formed to have asmaller height (or a smaller thickness) compared to that of the relatedart.

Also, the second bank pattern 105 is disposed in a contact hole which isformed in the planarization film 102 and used to connect the firstelectrode 103 and the drain electrode 206. The second bank pattern 105disposed in the contact hole can have a smaller height (or a smallerthickness). Due to the second bank pattern 105 having a smallerthickness, a curling phenomenon of the second bank pattern 105 in aphotolithography process which is used to pattern the second bankpattern 105 can be prevented.

The organic emission layer 106 is disposed on the substrate 100 providedwith the first bank pattern 104 and the second bank pattern 105. Indetail, the organic emission layer 106 can be disposed a region (i.e.,the emission region AA) surrounded by the second bank pattern 105. Suchan organic emission layer 106 can be formed using a liquefied organicemission material. The liquefied organic emission material used in theformation of the organic emission layer 106 can allow a large-sized OLEDdisplay device to be easily implemented.

To enhance light emission efficiency, the organic emission layer 106 canbe formed in a multi-layered structure including a hole injection layer,a hole transport layer, an emission material layer, an electrontransport layer and an electron injection layer. The organic emissionlayer 106 with the multi-layered structure can be formed by stackingalternately a hydrophilic organic emission layer with a hydrophobicorganic emission layer.

In this case, the first bank pattern 104 can be formed from ahydrophilic material. For example, the first bank pattern 104 can beformed from an inorganic material. Preferably, the first bank pattern104 can be formed from a silicon oxide SiO2. Also, the second bankpattern 105 can be formed from a hydrophobic material. For example, thesecond bank pattern 105 can be formed from an organic material.

In accordance therewith, the hydrophilic organic emission material canbe coated on the first bank pattern 104 in a uniform thickness. Also,the second bank pattern 105 formed from the hydrophobic material has aproperty of thrusting the organic emission material. As such, anoverflow of the liquefied organic emission material can be prevented.The second bank pattern 105 with hydrophilicity can be disposed in sucha manner as to expose a part of the upper surface of the first bankpattern 104 with hydrophobicity. In other words, the second bank pattern105 can be formed to have a narrower width than that of the first bankpattern 104. As such, a spread phenomenon of the organic emissionmaterial can be prevented.

The thin film transistor array substrate of the OLED display deviceaccording to the first embodiment of the present invention includes theplanarization film 102 with the opening exposing the boundary betweenthe color filter patterns different from each other within the secondnon-emission region NA2. As such, the second bank pattern 105 ofhydrophobicity disposed in the opening can be formed in a low height (ora small thickness). Also, the second bank pattern 105 disposed above thecontact hole A, which is used to connect the first electrode 103 and thedrain electrode 206, can have a small thickness (or a low height). Inaccordance therewith, the generation of the curling phenomenon of thesecond bank pattern 105 due to an etchant used in a photolithographyprocess can be prevented. Moreover, since the second bank pattern 105 isthinned, the organic emission layer 106 can be formed in a uniformthickness.

FIGS. 3A through 3C illustrate, subsequently, a method of fabricating athin film transistor array substrate of an OLED display device accordingto the first embodiment of the present invention. In further detail,FIGS. 3A through 3C are cross-sectional views illustrating a method offabricating a thin film transistor array substrate of an organic lightemitting diode display device according to the first embodiment of thepresent invention.

Referring to FIG. 3A, a color filter layer 101 is formed on a substrate100 and includes a red color filter pattern 101 a, a green color filterpattern 101 b and a blue color filter pattern. In particular, a redresin film is formed on the substrate 100. Then, the red resin film ispatterned through a photolithography process. In accordance therewith,the red color filter pattern 101 a can be formed on the substrate 100.Also, a green resin film is formed on the substrate 100 provided withthe red color filter pattern 101 a. Then, the green resin film ispatterned through the photolithography process. In accordance therewith,the green color filter pattern 101 b can be formed on the substrate 100.Moreover, a blue resin film is formed on the substrate 100 provided withthe red and green color filter patterns 101 a and 101 b. Then, the blueresin film is patterned through the photolithography process. Inaccordance therewith, the blue color filter pattern can be formed on thesubstrate 100. The red color filter pattern 101 a, the green colorfilter pattern 101 b and the blue color filter pattern can be arrangedalternately with one another.

Meanwhile, a black matrix can be formed on the substrate 100 using thephotolithography process before the color filter layer 101 is formed. Aplanarization material film 102 a is formed on the substrate 100provided with the color filter layer 101.

Referring to FIG. 3B, a photoresist material film is formed on theplanarization material film 102 a (refer to FIG. 3A). The photoresistmaterial film can be a photosensitive material which can be curedthrough light irradiation. Subsequently, a photoresist pattern is formedby performing exposure and development processes for the photoresistmaterial film using a mask with a transmission portion and aninterception portion. Then, the planarization material film 102 a isetched using the photoresist pattern as an etch mask, thereby forming aplanarization film 102.

The planarization film 102 cannot be disposed on (or can be removedfrom) a boundary between the color filter patterns different from eachother. In other words, the planarization film 102 can be formed in sucha manner as to be separated into at least two portions. As such, aportion of the planarization film 102 and another portion of theplanarization film 102 separated from each other can be disposedadjacently to each other. As the planarization film 102 is not disposedon the boundary between the color filter patterns different from eachother, an opening (or an opening gap) exposing the boundary between thedifferent color filter patterns can be formed in the planarization film102.

Then, a first electrode material layer is formed on the substrate 100provided with the planarization film 102. The first electrode materiallayer can be patterned into a first electrode 103 by being etchedthrough a photolithography process. Such a first electrode 103 can bedisposed on the planarization film 103. Afterward, a first bank materialfilm is formed on the substrate 100 in which the first electrode 103 isformed. The first bank material can be a hydrophilic material.

The first bank material film is patterned into a first bank pattern 104by being etched through the photolithography process. The first bankpattern 104 can be disposed in such a manner as to not only expose apart of the upper surface of the first electrode 103 within the emissionregion AA but also cover the opening within the second non-emissionregion NA2.

Referring to FIG. 3C, subsequently, a second bank material film isformed on the substrate 100 provided with the first bank pattern 104.The second bank material can be a hydrophobic material. Thereafter, thesecond bank material film is patterned into a second bank pattern 105 bybeing etched through the photolithography process. The second bankpattern 105 is disposed on the first bank pattern 104 covering theopening within the second non-emission region NA2.

In this way, the opening exposing the boundary between the color filterpatterns different from each other within the second non-emission regionNA2 is formed in the planarization film 102. As such, the second bankpattern 105 of hydrophobicity disposed above the opening can be loweredin height (or thinned in thickness). In accordance therewith, thegeneration of the curling phenomenon of the second bank pattern 105 dueto an etchant, which is used in the photolithography process patterningthe second bank pattern, can be prevented.

FIGS. 4 and 5 illustrate a thin film transistor array substrate of anOLED display device according to a second embodiment of the presentinvention. In further detail, FIG. 4 is a cross-sectional viewillustrating a thin film transistor array substrate of an OLED displaydevice according to the second embodiment of the present invention; andFIG. 5 is a cross-sectional view largely illustrating a non-emissionregion of the thin film transistor array substrate according to thesecond embodiment. A thin film transistor array substrate of the OLEDdisplay device of the second embodiment can have the same components asthat of the previous embodiment. As such, the description of the secondembodiment overlapping with the previously described embodiment will beomitted. Also, the components of the second embodiment being the sameshape and function as those of the previous embodiment will be referredto by the same reference numbers and names.

Referring to FIGS. 4 and 5, a thin film transistor array substrate of anOLED display device according to the second embodiment of the presentinvention includes a thin film transistor, a color filter layer 101 andan organic light emitting element. The thin film transistor includes asemiconductor layer 201, a gate insulation film 202, a gate electrode203, an inter-layer insulation film 204, a source electrode 205 and adrain electrode 206. The color filter layer 101 includes a red colorfilter pattern 101 a, a green color filter pattern 101 b and a bluecolor filter pattern. The organic light emitting element includes afirst electrode 103, an organic emission layer 106 and a secondelectrode 107.

In detail, the color filter layer 101 is disposed on a substrate 100which is defined into an emission region AA and first and secondnon-emission regions NA1 and NA2. The color filter layer 101 includesthe red color filter pattern 101 a, the green color filter pattern 101 band the blue color filter pattern 101 c.

A planarization film 112 is disposed on the substrate 100 provided withcolor filter layer 101. The planarization film 112 includes a firstplanarization film 112 a and a second planarization film 112 b. Thefirst planarization film 112 a is not disposed on a boundary between thecolor filter patterns different from each other within the secondnon-emission region NA2. Meanwhile, the second planarization film 112 bis disposed on the boundary between the different color filter patternswithin the second non-emission region NA2. In other words, the secondplanarization film 112 b is disposed in a region being not occupied bythe first planarization film 112 a. Also, the first planarization film112 a can be formed to have a higher height (or a larger thickness) thanthat of the second planarization film 112 b. As such, a recess (or adepressed portion) is formed in the planarization film 112 within thesecond non-emission region NA2.

The first electrode 103 of the organic light emitting element can bedisposed on the first planarization film 112 a within the emissionregion AA. The first electrode 103 can be used as an anode electrode.Such a first electrode 103 can be formed in a multi-layered structurewithout being limited to a structure shown in the drawings. Meanwhile,the organic light emitting element can further include a reflectionlayer disposed under the first electrode 103.

A first bank pattern 104 can be disposed on the second planarizationfilm 112 b within the second non-emission region NA2 of the substrate100 provided with the first electrode 103 of the organic light emittingelement. The first bank pattern 104 can be disposed in such a manner asto cover an edge of the first electrode 103.

In detail, the first bank pattern 104 can be disposed in such a manneras to not only expose a part of the upper surface of the first electrode103 within the emission region AA but also expand from one edge of thefirst electrode 103 up to the second non-emission region NA2. In otherwords, the first bank pattern 104 can be disposed in such a manner as tooverlap with the second planarization film 112 b within the secondnon-emission region NA2.

A second bank pattern 105 is disposed on the first bank pattern 104overlapping with the second planarization film 112 b within the secondnon-emission region NA2. The second bank pattern 105 can be formed tohave a small thickness (or a lowered height) because of being disposedon the second planarization film 112 b with a low height (or in therecess of the planarization film 112).

Also, the height of the second bank pattern 104 formed in a contact holeA, which is formed in the planarization film 112 and used to connect thefirst electrode 103 and the drain electrode 206, can be lowered. Assuch, the generation of a curling phenomenon of the second bank pattern105 due to an etchant, which is used in the photolithograph process forpatterning the second bank pattern 105, can be prevented.

The organic emission layer 106 is disposed on the substrate 100 providedwith the second bank pattern 105. The organic emission layer 106 can bedisposed in a region surrounded by the second bank pattern 105.

In this manner, the second bank pattern 105 is disposed in the recess ofthe planarization film 112 (or on the second planarization film 112 bwith the lowered height) within the second non-emission region NA2. Assuch, the second bank pattern 105 can be formed to have a smallthickness (or a lowered height). In accordance therewith, the organicemission layer 106 can also be formed to a flattened (planarized)surface.

To enhance light emission efficiency, the organic emission layer 106 canbe formed in a multi-layered structure including a hole injection layer,a hole transport layer, an emission material layer, an electrontransport layer and an electron injection layer. The organic emissionlayer 106 with the multi-layered structure can be formed by stackingalternately a hydrophilic organic emission layer with a hydrophobicorganic emission layer.

In this case, the first bank pattern 104 can be formed from ahydrophilic material. For example, the first bank pattern 104 can beformed from an inorganic material. Preferably, the first bank pattern104 is formed from a silicon oxide SiO2.

Meanwhile, the second bank pattern 105 disposed on the first bankpattern 104 within the second non-emission region NA2 can be formed froma hydrophobic material. For example, the second bank pattern 105 can beformed from an organic material. Also, the second bank pattern 105 withhydrophobicity can be disposed in such a manner as to expose a part(edges) of the upper surface of the first bank pattern 104 withhydrophilicity. In other words, the second bank pattern 105 can beformed to have a narrower width than that of the first bank pattern 104.In accordance therewith, a spread phenomenon of the organic emissionmaterial can be prevented.

The thin film transistor array substrate of the OLED display deviceaccording to the second embodiment of the present invention includes thesecond planarization film 112 b with the lowered height being disposedin the second non-emission region NA2. In other words, the thin filmtransistor array substrate can enable the recess (or the depressedportion) to be formed in the planarization film 112 within the secondnon-emission region NA2. As such, the height (or thickness) of thesecond bank pattern 105 can be lowered (or become smaller). Inaccordance therewith, the organic emission layer 106 can be formed tohave a flattened (or planarized) surface. Also, the height of the secondbank pattern 105 disposed in the contact hole A which is formed in theplanarization film 112 can be lowered. Therefore, the generation of thecurling phenomenon of the second bank pattern 105 due to an etchant usedin a photolithography process can be prevented.

FIGS. 6A through 6C illustrate, continuously, a method of fabricating athin film transistor array substrate of an OLED display device accordingto the second embodiment of the present invention. In further details,FIGS. 6A through 6C are cross-sectional views illustrating a method offabricating a thin film transistor array substrate of an OLED displaydevice according to the second embodiment of the present invention. Thethin film transistor array substrate of the OLED display device of thesecond embodiment can have the same components as that of the previousembodiment. As such, the description of the second embodimentoverlapping with the previously described embodiment will be omitted.Also, the components of the second embodiment being the same shape andfunction as those of the previous embodiment will be referred to by thesame reference numbers and names.

Referring to FIG. 6A, a color filter layer 101 is formed on a substrate100 using a photolithography process. The color filter layer 101includes a red color filter pattern 101 a, a green color filter pattern101 b and a blue color filter pattern. Also, a black matrix can beformed on the substrate 100 using the photolithography process beforethe color filter layer 101 is formed. A planarization material film 102a is formed on the substrate 100 in which the color filter layer 101 isformed.

Referring to FIG. 6B, a negative photoresist material film is formed onthe planarization material film. The photoresist material film can be aphotosensitive material which can be cured through light irradiation.Also, a photoresist pattern is formed by performing exposure anddevelopment processes for the photoresist material film using a maskwith a transmission portion, a semi-transmission portion and aninterception portion. The transmission portion of the mask transmitslight without changing any characteristics of the light. Thesemi-transmission portion of the mask transmits a smaller quantity oflight compared to the transmission portion, and the interception portionof the mask completely intercepts light.

As such, a portion of the photoresist material film opposite to thesemi-transmission portion of the mask can be semi-cured by being exposedto light. Also, another portion of the photoresist material filmopposite to the transmission portion of the mask can be completely curedby being exposed to light.

In accordance therewith, one portion of the photoresist material filmopposite to the transmission portion of the mask can become onephotoresist pattern disposed on a first planarization film with a highheight after the semi-curing of the photoresist material film. Also,another portion of the photoresist material film opposite to thesemi-transmission portion of the mask can become another photoresistpattern disposed on a second planarization film with a low height afterthe semi-curing of the another photoresist material film. Moreover,still another portion of the photoresist material film opposite to theinterception portion of the mask is completely removed from theplanarization material film and exposes the planarization material film.Alternatively, the photoresist material film can be formed from apositive photoresist material. In this case, a mask must be fabricatedin an inverse pattern unlike the above-mentioned mask.

The exposed planarization material film is etched using a photoresistpattern, which is formed in a region opposite to the transmission andsemi-transmission portions of the mask, as an etch mask. At this time,the planarization material film within a contact hole region can beremoved by a first thickness. Thereafter, the first photoresist patterncan be partially removed from the planarization material film through anashing process. As such, a part of the photoresist pattern disposed onthe first planarization film, which will be formed later, remains and isnot completely removed from the planarization material film. Meanwhile,another part of the photoresist pattern disposed on the secondplanarization film, which will be formed later, is completely removedfrom the planarization material film.

Subsequently, the planarization material film is etched by a secondthickness using the residual photoresist pattern disposed on the firstplanarization, which will be formed as an etch mask after thephotoresist is semi-cured. As such, the first planarization film 112 awhich is the same as one portion of the planarization material filmdisposed under the residual photoresist pattern can be formed. Also, thesecond planarization film 112 b which is the same as the partiallyetched portion of planarization material film can be formed. The secondplanarization film 112 b is formed to have a lower height (or a smallerthickness) than that of the first planarization film 112 a. In otherwords, a recess (or a depressed portion) is formed in the planarizationfilm 112 within the second non-emission region NA2. Moreover, a contacthole A can be simultaneously formed at the formation of the secondplanarization film 112 b.

Referring to FIG. 6C, a first electrode material layer is formed on thesubstrate 100 provided with the planarization film 112. The firstelectrode material layer can be patterned into a first electrode 103 bybeing etched through a photolithography process. Such a first electrode103 can be disposed on the first planarization film 112 a. Afterward, afirst bank material film is formed on the substrate 100 in which thefirst electrode 103 is formed. The first bank material can be ahydrophilic material.

The first bank material film is patterned into a first bank pattern 104by being etched through the photolithography process. The first bankpattern 104 can be disposed in such a manner as to not only expose apart of the upper surface of the first electrode 103 within the emissionregion AA but also cover the second planarization film 112 b within thesecond non-emission region NA2.

Subsequently, a second bank material film is formed on the substrate 100provided with the first bank pattern 104. The second bank material canbe a hydrophobic material. Thereafter, the second bank material film ispatterned into a second bank pattern 105 by being etched through thephotolithography process. The second bank pattern 105 is disposed on thefirst bank pattern 104 covering the second planarization film 112 bwithin the second non-emission region NA2.

In this way, the second planarization film 112 b with the lowered heightcan be disposed in the second non-emission region NA2. In other words,the recess (or the depressed portion) can be formed in the planarizationfilm 112 within the second non-emission region NA2. As such, the height(or thickness) of the second bank pattern 105 with hydrophobicity can belowered (or become smaller). In accordance therewith, the organicemission layer 106 can be formed to have a flattened (or planarized)surface. Also, the height of the second bank pattern 105 disposed in thecontact hole A which is formed in the planarization film 112 can belowered. Therefore, the generation of the curling phenomenon of thesecond bank pattern 105 due to an etchant used in a photolithographyprocess can be prevented.

FIG. 7 illustrates a thin film transistor array substrate of an OLEDdisplay device according to a third embodiment of the present invention.In further detail, FIG. 7 is a cross-sectional view illustrating a thinfilm transistor array substrate of an OLED display device according tothe third embodiment of the present invention. The thin film transistorarray substrate of the OLED display device of the third embodiment canhave the same components as those of the previous embodiments. As such,the description of the third embodiment overlapping with the previouslydescribed embodiments will be omitted. Also, the components of the thirdembodiment being the same shape and function as those of the previousembodiments will be referred to by the same reference numbers and names.

Referring to FIG. 7, a thin film transistor array substrate of the OLEDdisplay device according to the third embodiment of the presentinvention includes an emission region AA, a first non-emission regionNA1 and a second non-emission region NA2. The first non-emission regionNA1 is used as a driver region in which a thin film transistor isdisposed. The second non-emission region NA2 corresponds to the rest ofa pixel region with the exception of the emission region AA and thefirst non-emission region NA1.

A planarization film 122 is disposed on a substrate 100 in which thethin film transistor is formed. The planarization film 122 is disposedon the substrate 100 except for a part of the substrate 100 in thesecond non-emission region NA2. An opening can be formed in theplanarization film 122 by removing a part of the planarization film 122in the second non-emission region NA2.

Also, a first electrode 103 of an organic light emitting elementconnected to a drain electrode 206 of the thin film transistor isdisposed on the planarization film 122. A first bank pattern 104 can bedisposed in the first and second non-emission regions NA1 and NA2 of thesubstrate 100 provided with the first electrode 103 of the organic lightemitting element. In other words, the first bank pattern 104 is disposedin the opening within the second non-emission region NA2.

Moreover, a second bank pattern 105 can be disposed in such a manner asto overlap with the first bank pattern 104 covering the opening. Inother words, the first bank pattern 104 can be disposed in the openingand the second bank pattern 105 can be disposed on the first bankpattern 104. As such, the height (or thickness) of the second bankpattern 105 can be lowered (or become smaller). The second bank pattern105 is also disposed in a contact hole A which is formed in theplanarization film 122 and used to connect the first electrode 103 andthe drain electrode 206. The height (thickness) of the second bankpattern 105 disposed in the contact hole A can also be lowered (orbecome smaller). In accordance therewith, the generation of a curlingphenomenon of the second bank pattern 105 in a photolithography processwhich is used for patterning the second bank pattern 105 can beprevented.

Next, FIG. 8 illustrates a thin film transistor array substrate of anOLED display device according to a fourth embodiment of the presentinvention. In further detail, FIG. 8 is a cross-sectional viewillustrating a thin film transistor array substrate of an OLED displaydevice according to the fourth embodiment of the present invention. Thethin film transistor array substrate of the OLED display device of thefourth embodiment can have the same components as that of the previousembodiments. As such, the description of the fourth embodimentoverlapping with the previously described embodiments will be omitted.Also, the components of the fourth embodiment being the same shape andfunction as those of the previous embodiments will be referred to by thesame reference numbers and names.

Referring to FIG. 8, a thin film transistor array substrate of an OLEDdisplay device according to the fourth embodiment of the presentinvention is defined into an emission region AA, a first non-emissionregion NA1 and a second non-emission region NA2. A planarization film132 is disposed on a substrate 100 in which a thin film transistor isdisposed. The planarization film 132 includes a first planarization film132 a and a second planarization film 132 b.

The first planarization film 132 a is disposed in the rest of thesubstrate 100 with the exception of a part of the second non-emissionregion NA2. In other words, an opening can be formed in the firstplanarization film 132 a within the second non-emission region NA2 byremoving a part of the first planarization film 132 a from the secondnon-emission region NA2. Meanwhile, the second planarization film 132 bis disposed in the opening. The second planarization film 132 b isformed to have a lower height than that of the first planarization film132 a. Consequently, a recess (or a depressed portion) is formed in theplanarization film 132 within the second non-emission region NA2.

A first bank pattern 104 and a second bank pattern 105 overlapping withthe first bank pattern 104 are sequentially disposed on the secondplanarization film 132 b with the low height (or small thickness). Inaccordance therewith, the height (or thickness) of the second bankpattern 105 can be lowered (or become smaller). The second bank pattern105 overlapping with the first bank pattern 104 is also disposed in acontact hole A which is formed in the planarization film 132 and used toconnect a first electrode 103 and a drain electrode 206. Also, theheight (thickness) of the second bank pattern 105 disposed in thecontact hole A can be lowered (or become smaller). In accordancetherewith, the generation of a curling phenomenon of the second bankpattern 105 in a photolithography process which is used for patterningthe second bank pattern 105 can be prevented.

FIG. 9 is a photograph illustrating a non-emission region of a thin filmtransistor array substrate of an OLED display device according to anembodiment of the present invention. As illustrated in FIG. 9, anopening with a width of about 32.1 μm is formed in a planarization filmwithin a non-emission region. Also, one portion of a second bank patterndisposed in the opening of the planarization film is formed in a height(or thickness) of about 2.83 μm. Meanwhile, another portion of thesecond bank pattern disposed on the planarization film is formed inanother height (thickness) of about 1.92 μm. In other words, because theplanarization film is removed from the non-emission region by at least afixed thickness, an organic emission layer can be formed to have aflattened (or planarized) surface.

The above-mentioned features, structures, effects and so on of thepresent invention are included in at least one embodiment without beinglimited to only a single embodiment. Although the present invention hasbeen explained regarding only the embodiments described above, it shouldbe understood by the ordinary skilled person in the art that the presentinvention is not limited to these embodiments. Rather, various changesor modifications thereof are possible without departing from the spiritof the present invention. More particularly, various variations andmodifications are possible in the component parts which are described inthe embodiments. Accordingly, the scope of the present invention shallbe determined only by the appended claims and their equivalents withoutbeing limited to the detailed description.

What is claimed is:
 1. An organic light emitting diode (OLED) displaydevice, comprising: a substrate; a first bank pattern formed on thesubstrate and in an emission region and a non-emission region; a secondbank pattern formed on the first bank pattern; an organic emission layerformed on the substrate in the emission region; and a planarization filmformed on the substrate to include an opening under the first and secondbank patterns in the non-emission region, wherein the second bankpattern is on the first bank pattern in the non-emission region, and thefirst bank pattern is in the opening of the planarization film in thenon-emission region.
 2. The OLED display device according to claim 1,wherein the first bank pattern includes a concave portion in the openingof the planarization film, and a portion of the second bank pattern isformed above the concave portion of the first bank pattern.
 3. The OLEDdisplay device according to claim 2, wherein a center of the portion ofthe second bank pattern is horizontally aligned with a center of theopening of the planarization film.
 4. The OLED display device accordingto claim 3, wherein a bottom surface of the portion of the second bankpattern is wider than a top surface of the portion of the second bankpattern.
 5. The OLED display device according to claim 1, furthercomprising: a color filter layer formed directly below the first bankpattern in the non-emission region, the color filter layer includingcolor filter patterns, wherein a boundary region between the colorfilter patterns is below the opening of the planarization film.
 6. TheOLED display device according to claim 5, wherein the planarization filmis not disposed above the boundary region between the color filterpatterns.
 7. The OLED display device according to claim 5, wherein thefirst bank pattern includes a concave portion to contact a thin portionof the planarization film that is in the opening of the planarizationfilm.
 8. The OLED display device according to claim 1, furthercomprising: a thin film transistor formed on the substrate in anothernon-emission region; a first electrode formed on the thin filmtransistor; and a contact hole formed in the another non-emission regionto connect the first electrode to the thin film transistor.
 9. The OLEDdisplay device according to claim 8, wherein another portion of each ofthe first and second bank patterns is disposed on the first electrode inthe contact hole.
 10. The OLED display device according to claim 9,wherein an edge of the concave portion of the first bank pattern formedin the non-emission region overlaps the first electrode at a side of theemission region, and an edge of another concave portion of the firstbank pattern formed in the another non-emission region overlaps thefirst electrode at another side of the emission region.
 11. A method offorming an organic light emitting diode (OLED) display device, themethod comprising: forming a first bank pattern on a substrate and in anemission region and a non-emission region; forming a second bank patternon the first bank pattern; forming an organic emission layer on thesubstrate in the emission region; and forming a planarization film onthe substrate to include an opening under the first and second bankpatterns in the non-emission region, wherein the second bank pattern ison the first bank pattern in the non-emission region, and the first bankpattern is in the opening of the planarization film in the non-emissionregion.
 12. The method according to claim 11, wherein the first bankpattern includes a concave portion in the opening of the planarizationfilm, and a portion of the second bank pattern is formed above theconcave portion of the first bank pattern.
 13. The method according toclaim 12, wherein a center of the portion of the second bank pattern ishorizontally aligned with a center of the opening of the planarizationfilm.
 14. The method according to claim 13, wherein a bottom surface ofthe portion of the second bank pattern is wider than a top surface ofthe portion of the second bank pattern.
 15. The method according toclaim 11, further comprising: forming a color filter layer directlybelow the first bank pattern in the non-emission region, the colorfilter layer including color filter patterns, wherein a boundary regionbetween the color filter patterns is below the opening of theplanarization film.
 16. The method according to claim 15, wherein theplanarization film is not disposed above the boundary region between thecolor filter patterns.
 17. The method according to claim 15, wherein thefirst bank pattern includes a concave portion to contact a thin portionof the planarization film that is in the opening of the planarizationfilm.
 18. The method according to claim 11, further comprising: forminga thin film transistor on the substrate in another non-emission region;forming a first electrode on the thin film transistor; and forming acontact hole in the another non-emission region to connect the firstelectrode to the thin film transistor.
 19. The method according to claim18, wherein another portion of each of the first and second bankpatterns is disposed on the first electrode in the contact hole.
 20. Themethod according to claim 19, wherein an edge of the concave portion ofthe first bank pattern formed in the non-emission region overlaps thefirst electrode at a side of the emission region, and an edge of anotherconcave portion of the first bank pattern formed in the anothernon-emission region overlaps the first electrode at another side of theemission region.